A control network is a network of nodes that collectively monitor, sense, and control or enable control of an environment for a particular purpose. A home appliance network is a good example of a control network. In fact, thousands of control networks already exist in everyday life in automobiles, refrigerators, traffic light controls, city lighting systems, and on factory floors. Control networks vary enormously in the number of nodes (from three to thousands) in the network and in their complexity. Unlike networks that people use to communicate with each other, control networks tend to be invisible. In the future, control networks are expected to become an important aspect of what is sometimes called ubiquitous computing.
Communication between nodes in a control network may be peer-to-peer or master-slave. The nodes in some control networks contain three processors in one: two dedicated to moving data within the network and one for the specialized program associated with that node. This modularity makes it cheaper and faster to build new processors for control networks. Increasingly, control networks are being made from off-the-shelf hardware and software components.
One future role for control networks will be as the controllers of microelectromechanical sytems (MEMS), sometimes referred to as smart matter. Because it greatly expands the number of items in the world that can be uniquely addressed in a network, IPv6, a new version of the Internet Protocol (IP), is expected to make remote access and control of all kinds of devices possible, including every networked appliance at your office or at home. Sun Microsystem's Jini, will make it easy to plug new devices into a control network and have their characteristics immediately recognized by the system.